[Metastatic gastrointestinal hepatoid adenocarcinoma of the liver: a high-grade carcinoma that is easily confused with primary hepatocellular carcinoma].

Objective: To investigate the clinicopathologic and immunophenotypic features of metastatic gastrointestinal hepatoid adenocarcinomas in the liver. Methods: Eight cases of hepatic metastatic gastrointestinal hepatoid adenocarcinoma diagnosed at the Affiliated Drum Tower Hospital, Nanjing University Medical School from January 2009 to January 2019 were retrospectively analyzed. The clinical data, histopathologic features and immunohistochemical (IHC) characteristics performed by EnVision method were analyzed. Results: There were five males and three females with a mean age of 66 years. The primary sites included one case each from the distal esophagus and the right colon, and the other six cases were from the stomach. Pre-treatment serum AFP levels were increased in four patients, normal in two, and was not known in two other patients. Liver metastases occurred in all eight patients at initial diagnosis. Microscopically, the primary tumor was composed of areas showing hepatic differentiation with or without typical adenocarcinoma component; and the areas with hepatic differentiation morphologically resembled hepatocellular carcinoma (HCC). IHC staining showed variable expression of HCC markers such as Glypican 3, AFP, SALL4 and HepPar-1, and gastrointestinal adenocarcinoma markers such as CK19, CDX-2 and Villin in both the primary and metastatic foci of hepatoid adenocarcinoma. Conclusions: Hepatoid adenocarcinoma in the digestive tract gives rise to only non-specific symptoms, and shows high propensity for invasion and metastasis. When liver metastasis is the presenting symptom, it is difficult to distinguish metastatic hepatoid adenocarcinoma from the primary HCC based on histopathologic characteristics alone. The accurate diagnosis of metastatic hepatoid adenocarcinoma in the liver requires combination of clinical, radiologic, histopathologic and IHC findings.目的： 探讨肝脏转移性消化道肝样腺癌（hepatoid adenocarcinoma）病例的临床病理学和免疫表型特征。 方法： 回顾性分析2009年1月至2019年1月在鼓楼医院诊治的8例肝脏转移性消化道肝样腺癌患者的临床资料、病理组织学形态以及免疫组织化学（EnVision法）表达特点。 结果： 患者男性5例，女性3例，平均年龄66岁。原发于远端食管1例，原发于右半结肠1例，其余6例均原发于胃。4例患者治疗前血清甲胎蛋白（AFP）升高，2例血清AFP水平正常，2例结果不详。8例患者初诊时均有肝转移。镜下观察：原发部位肿瘤组织由肝样分化区构成，伴或不伴普通腺癌成分，肝样分化区组织学特点似典型肝细胞肝癌（hepatocellular carcinoma, HCC）。而肝脏转移灶组织学形态以肝样分化为主，与HCC难以鉴别。免疫表型上，原发灶与转移灶肝样分化区域不同程度表达HCC的标志物如Glypican 3、AFP、SALL4和HepPar-1；同时也表达消化道腺癌的标志物，如细胞角蛋白（CK）19、CDX-2和Villin等。 结论： 消化道肝样腺癌临床症状不特异，有较强的侵袭和转移能力。当以肝脏转移灶为首发症状时，仅根据组织病理学特征很难与肝脏原发性HCC相鉴别。肝脏转移性肝样腺癌需要综合临床、影像学、组织病理学以及免疫组织化学检查等结果才能够得出准确诊断。.